Franz Ferdinand's third album has had a difficult gestation. Before Kylie collaborator Dan Carey took the production helm, there were abortive sessions with the eclectic DJ and producer Erol Alkan, talk of African influences and, most intriguing, an attempt to work with Girls Aloud's visionary production team Xenomania. Alas, the latter collapsed owing to the kind of musical differences you suspect may have involved Franz Ferdinand recognising their own limitations. You might talk a good fight about wanting to make music that makes girls dance, but you don't know how indie you really are until you get in the studio with someone who actually makes girls dance for a living.

This is unmistakably the behaviour of musicians who know a sonic overhaul is needed. The post-punk revival Franz helped set in motion has long been running on fumes, while the success of their second album, 2005's You Could Have It So Much Better, involved some sleight of hand - a sprinkling of strong singles covering its deficiencies long enough to confuse certain reviewers, including the present writer. These facts can't have escaped a band that always seemed a little cannier and more ambitious than their peers.

Perhaps Franz Ferdinand are a little too canny, at least for the kind of bold, confounding reinvention that Tonight purports to be. Instead, it sounds like an album of second or third thoughts, the desire to throw caution to the wind tempered by a fear of straying too far from one's musical comfort zone in uncertain times: so the choppy guitars, disco drums and lyrics archly contemplating sexual relationships remain, albeit joined by synthesisers. You sense that compromises have been made between the desire to do something artistically challenging and the desire to retain both continuity and fanbase, and that, often, the compromise reached is the wrong one. In a recent interview, Franz talked about "dialling down" the choruses of Tonight's tracks to make them seem less obviously commercial: Ulysses and Live Alone aside, attention-grabbing tunes are certainly noticeable by their absence. But if you're going to wilfully ignore the pop sensibility that made your earlier efforts irresistible, you'd better have something amazing in its place. It's no good just buying a synthesiser and keeping your fingers crossed.

To be fair, there are moments when Tonight amounts to more than that, particularly towards the end of the album. Lucid Dreams unexpectedly and thrillingly transforms midway through into buzzing, vaguely unhinged cosmic disco. Dream Again is an appealingly off-kilter, vaguely dub-inspired electronic ballad. Both might point the way to Franz Ferdinand's future: the shame is that they aren't more representative of their present. Listening to them, you think: why didn't you make a whole album like this?